1. Field of the Invention
The present invention relates to the field of electronic devices. In particular, the present invention relates to determinations of whether or not such a device is in use.
2. Background of the Invention
“Screensaver” functionality is a typical attribute of electronic devices. Typically, such a screen will be a blank screen or a screen displaying some standard pattern. Historically, such functionality was built into personal computers to prevent “phosphor burn-in” on Cathode Ray Tube (CRT) screens, but it also came to be built into mobile telephone liquid crystal display (LCD) screens to, for example, prolong battery life. The screensaver on an LCD screen more often simply deactivates the backlight.
The typical method by which a device determines whether or not it is in use is to determine how long it has been since the device has received a user input. If this time exceeds some pre-determined threshold time, the device displays the screensaver. The screensaver is then displayed until the device next receives a user input, whereupon the screen returns to what it displayed before the screensaver was activated.
However, this method of determining whether or not the device is in use presents several drawbacks. First, this method requires a user input to return the display from the screensaver. In some cases, this user input might affect whatever application the user was running on the device. For example, if the device is a mobile telephone and the user is typing a text message when the screensaver comes, the user may hit the letter “A” repeatedly to return the display to the text message. This may cause a series of “A's” to be included in the text message, which the user would have to delete. Second, detecting whether or not any user input has been received in a given time period is, in many cases, a poor way to determine whether or not the device is actually in use. For example, a user of an instant messaging application might need to wait a long time to receive a response from the party he/she is messaging. In such a case, if the time the user waits exceeds the threshold time of the screensaver, then the screensaver is activated even though the user is still using the device. Users can evade this problem by increasing the threshold time of the screensaver, but such a solution still presents problems. Any increased threshold the user selects might not be large enough to prevent the activation of the screensaver for all cases where the user is using the device but not creating any user input. Also, increasing the threshold time means that in cases where the device is not in fact in use, the screensaver will then not be activated for a longer period of time. Third, reception of user input can, in some cases, be an ambiguous signal that the user wishes to return the display to its display prior to the activation of the screensaver. For example, if the user hits an “A” button as a user input to return the device to its display before the screensaver was activated, the user may not know whether or not this input has actually been received by the device. For example, it may not be clear whether or not this button was pressed hard enough for it to be interpreted by the device as user input. For this reason, a user may furiously and repeatedly hit a button upon the display of the screensaver when the device is actually in use.
Research has shown that users of electronic devices not creating any user input nevertheless frequently rest their fingers on the keyboard, touch screen, or other areas of the electronic device. For example, users reading email, web pages, or performing ‘vigilance tasks’, such as where the user is waiting for some event or for another user to respond to an instant message, frequently rest their fingers on the keyboard of the electronic device.
Furthermore, technologies to detect the presence of a human stimulus, such as the pressure created by fingers resting on a keyboard, are known in the art and recently have been integrated into portable electronic devices. For example, touch screens, which allow users to interact with devices through human touch, are now available. Two-way capacitive transducers and other touch-screen technologies can detect a variety of human stimuli including the conductivity of skin; the specific motions associated with natural muscular twitches; the pressure variations associated with pulse; the temperature of skin; etc. Such technologies use a variety of means and metrics to detect these stimuli, including galvanic response for measuring skin conductivity; capacitive systems utilizing indium tin oxide for measuring the steady pressure of fingers resting on keys; thermocouples for measuring the warmth of the skin; etc. All of these technologies enable humans to interact with devices through the use of human stimulus alone, without intervening buttons or other means of input.
Moreover, as concerns about energy use become widespread, more sophisticated techniques to detect when electronic devices are or are not in use are becoming increasingly important to consumers and producers of such devices.
Thus, there is a clear need for screensaver functionality which uses a method to determine whether or not the device is in use beyond just whether or not the device has received user input.